SP edition configuration knobs

BGP/PCEP is currently included in the SP distribution, where it contains a few contributions to the default configuration of that package.

The unfortunate side-effect is the need to synchronize configuration changes across repositories, and results in at least one broken distribution package.

To remedy this, devise a strategy how both BGP and PCEP parts of this project can contribute files to the configuration and transition the configuration files into BGP/PCEP repository, where they can be atomically updated.